Power converters typically serve to accept energy from an unregulated energy source, such as a voltage source, and derive therefrom a regulated voltage which is applied to a load circuit. The regulation function is performed by interposing a voltage regulator device between the source of energy and the load circuit. One such type of voltage regulator is known as a switching regulator or switching power supply. These devices employ switching devices that operate in either a fully on state or a fully off state. The switching device is periodically turned on for a time interval to permit energy transfer around the various elements of the power train for purposes of maintaining the voltage output at a predetermined level. The device is then periodically turned off to allow the energy to decay into the load. A feedback signal from the output of the regulator is fed back to a control circuit. The control circuit utilizes the feedback signal to continuously adjust the duty cycle and/or frequency of the control signal driving the power switches in responses to variations in the output load and input voltage, and as a result, regulating the output voltage.
Typically, the power switches are turned on and off at a frequency which varies with the application and given size, cooling, power output, temperature and efficiency constraints. In certain applications, it may be required that the output signal is electrically isolated from the input signal, for example, via a transformer. In these applications, it will be required that the feedback signal be electrically isolated from the control circuit. Therefore, the switching regulator will require DC feedback components that work across said isolation boundary such as opto-isolators or additional signal transformers that add cost and complexity to the switching regulator.